Add concrete antifreeze not afraid of freezing ? Can t freeze?

The addition of antifreeze to the concrete in winter is not not afraid of freezing, but the freezing temperature is reduced, so that it is not easy to freeze.

The purpose of adding antifreeze to concrete is to delay the effective time of construction. For example, the original 0 degree concrete does not set properly. With the addition of antifreeze, it can be lowered to -5 degrees. But still afraid of freezing.

1. The purpose of adding antifreeze to concrete is to delay the effective time of construction, such as the original 0 degree concrete can not be set normally. With the addition of antifreeze, it can be lowered to -5 degrees. Concrete is still afraid of freezing. Not to mention that I can't freeze!!

2. There is a difference between concrete antifreeze and antifreeze concrete.

That's not true. It is to lower the freezing point. For example, the original 0 degree concrete cannot set normally. With the addition of antifreeze, it can be lowered to -5 degrees.

No, there is a maximum value limit for additives, such as Xinjiang, Heilongjiang and other regions. If you want to construct, you have to add people and stones, use hot water, maintain and heat preservation, etc.

There are three main aspects of concrete anti-freezing ideas: (1).The use of early strength agent to greatly improve the early strength of concrete, concrete inside the cement hydration is sufficient, the residual capillary pores in the free water is relatively less, coupled with the concrete has a certain strength can resist the expansion stress of water freezing, some water glue is relatively small after the addition of early strength agent, 2-3 days of time inside the concrete has been self-drying, there is no free water, naturally not afraid of freezing.

2).The use of admixtures that can reduce the freezing point of water, such as sodium nitrite, can reduce the freezing point of water to minus 20 degrees Celsius, and the capillary free water left in the concrete by sodium nitrite will play a role in preventing free water from freezing, but the limit, more than minus 20 degrees Celsius, will still freeze and destroy the concrete. It is important to know that the expansion stress of water completely freezing in the concrete pores can reach hundreds of megapascals.

3).The use of air-entraining agent to introduce fine bubbles provides a certain volume space for water to freeze and eliminates expansion stress. The current antifreeze is generally a composite agent, that is, by the early strength of chloride salt, sulfate, there is also sodium nitrite and air entraining agent to reduce the freezing point of water, that is, it can reduce the amount of free water in the concrete, improve the early strength of the concrete, prevent the concrete from freezing, and can also reduce the freezing point of the water and provide a certain volume of space for free water freezing.

However, thermal insulation measures must be taken during construction.

Concrete antifreeze setting time difference.

The national standard stipulates that it is -210 +210minThis means that the setting time of the inspected concrete is 210 minutes earlier or 210 minutes later than the benchmark is acceptable.

The amount of antifreeze used in concrete should be adjusted in time according to the specific temperature fluctuation to ensure the antifreeze and early strength effect of the antifreeze. The dosage of antifreeze should be controlled within a certain range, because some of the antifreeze and early strength components in the antifreeze are directly involved in the hydration process of cement, and if the amount of antifreeze is too much, it will affect the durability of the concrete structure. Therefore, if the temperature is too low beyond the application range of antifreeze, we should still pay attention to the insulation and maintenance measures of the newly poured concrete to avoid freezing damage to the concrete.

Antifreeze is added to concrete at minus 4 degrees. Usually below zero to add antifreeze, because in a low temperature environment, the concrete will harden, affecting the use, after adding antifreeze, can prevent hardening. Antifreeze can reduce the freezing point in concrete, and can be mixed with water reducer and air-entraining agent for better results.

And when the temperature of the concrete is low, the surface can be covered with a layer of plastic film and straw bags, and it is best to take thermal insulation measures to prevent the surface from being frozen and cracked.

Precautions for concrete with antifreezeThe precautions for using antifreeze concrete and antifreeze should pay attention to the mixing method: for salts containing insoluble matter or low solubility in antifreeze, they must be ground into powder and then mixed with cement. When it needs to be prepared into a solution, it should be fully dissolved and stirred evenly, and its concentration and the amount of each addition should be strictly controlled.

If the composite antifreeze is used, their co-solubility should be considered, if not, they should be prepared into a solution separately and then added to the concrete.

In order to speed up the dissolution, 40 60 hot water can be used to prepare a solution and then add it to the concrete respectively. If the antifreeze added in powder form is damp and agglomerate, it should be ground fine and passed through a sieve before it can be used.

1.Working performance of freshly mixed concrete. Different antifreeze components have different effects on the workability of concrete.

The early plasticizing effect of sodium nitrite on concrete has improved the slump of concrete. However, sodium nitrite increases the alkalinity of the concrete and accelerates the dissolution of C3A, resulting in the formation of more aluminite, resulting in a decrease in fluidity. As a non-ionic surfactant, ethylene glycol is adsorbed on the surface of cement particles, which can make cement particles better dispersed in solution, and also slow down the diffusion rate of cement particles, and play a role in slowing down, so the initial slump of concrete mixed with ethylene glycol has been improved, and the slump loss of 30min has been greatly reduced, and with the increase of ethylene glycol content, this phenomenon has become more and more significant; The initial slump of concrete mixed with calcium nitrate did not change significantly, and the 30min slump loss increased significantly with the increase of the dosage.

2.Concrete setting time. The early strength components in antifreeze (such as potassium carbonate, calcium chloride, etc.) tend to shorten the setting time of concrete, which is conducive to the hardening of concrete; However, organic antifreeze (e.g. ethylene glycol, etc.) will increase the setting time of concrete.

If the setting time is not grasped well, it may cause inconvenience to the soil, so the setting time of concrete should be reasonably selected or adjusted by the composite of different components.

Antifreeze doesn't have much effect on concrete, but if the temperature is low, try not to cause concrete, after all, it's still not good.

Hello, antifreeze is generally mixed with inorganic salts as antifreeze components, such as nitrate, chloride, nitrite, etc., organic substances such as triethanolamine, polyethanol, etc., but the current antifreeze components mainly add nitrite, which contains highly toxic, so the general antifreeze is toxic. As an economical and durable building structure, concrete has become the most widely used and widely used building material in the world today, and thus has attracted more and more attention. With the continuous progress of construction technology, the requirements for concrete are getting higher and higher.

Concrete should not only have the properties of adjustable coagulation, early strength, light weight, high strength, low heat of hydration, high fluidity, high compactness, high durability and high toughness, but also be able to be constructed in various environments such as high temperature and low negative temperature, but also low cost, easy to form and simple to maintain.

The main purpose of adding antifreeze to concrete is to maintain sufficient liquid phase at negative temperature, so that the hydration of cement can continue to be carried out; After turning to a positive temperature, the concrete strength can further increase and reach or exceed the design mark. Empty letter base.

Premature freezing of concrete poured in winter without antifreeze will greatly reduce the ultimate strength, and the strength loss rate may reach 50 of the design mark, and even cause overall structural failure.

The freezing point of the aqueous solution will be reduced by adding a certain amount of antifreeze to the mixing water of concrete, and the reduction of the freezing point is related to the type and amount of antifreeze or the concentration of the solution. The effectiveness of antifreeze depends largely on the concentration of the solution and the negative temperature values experienced by the concrete hardening process.

When the average outdoor daily temperature is stable below 5°C for 5 consecutive days, the construction process is called winter construction. In this case, antifreeze can be added to prevent early frost damage.

The early strength antifreeze adopts special antifreeze materials, which can effectively reduce the freezing point of concrete and mortar, and greatly improve the frost resistance of concrete and mortar at negative temperature. And it can increase the early strength of concrete and mortar by more than 80%, and the later strength will not be reduced, so as to ensure that the strength is developed in the same way under the conditions of positive and negative temperature and negative temperature. The results are remarkable.

-15 degrees Celsius. Concrete antifreeze can generally resist about minus 15 degrees to ensure that it will not solidify and freeze at about minus 15 degrees, so this antifreeze should be used according to this standard. According to its composition, concrete antifreeze can be divided into strong electrolyte inorganic salts (chloride salts, chloride salt rust inhibitors, chloride-free salts), water-soluble organic compounds, organic compounds and inorganic salts compounds, and composite antifreeze.

Concrete, referred to as concrete, refers to the general term of engineering composite materials that are cemented into a whole by cementitious materials. The word concrete usually refers to the use of cement as cementitious material, sand and stone as aggregates; Cement concrete, also known as ordinary concrete, is widely used in civil engineering engineering by mixing, forming and curing cement concrete obtained by mixing with water (with or without admixtures and admixtures) in a certain proportion.

The effective freeze protection time is before the concrete reaches the critical strength of frost resistance. After the concrete reaches the critical strength, it is not afraid of freezing, and the antifreeze effect of the antifreeze agent does not work. But only if the antifreeze is a qualified product.

As for how long it is, it is related to factors such as air temperature, mold temperature, covering, and maintenance methods, and cannot be generalized.

Antifreeze is generally an antifreeze early strength, which can reduce the freezing point of concrete in winter, and does not freeze at low temperatures, and has an early strength effect, that is, it accelerates the setting speed of concrete. If you say that the setting time is delayed by adding antifreeze, it should be that the concrete sets slowly due to low temperature, and if it is not mixed, it is easy to freeze.

The use of early strength agent to greatly improve the early strength of concrete, concrete inside the cement hydration is sufficient, the residual capillary pores in the free water is relatively less, coupled with the concrete has a certain strength can resist the expansion stress of water freezing, some water glue is relatively small after the addition of early strength agent, 2-3 days of time inside the concrete has been self-drying, there is no free water, naturally not afraid of freezing.

It is hoped that it will be listed as a satisfactory response.

If you add a large amount, it will always work, and as long as it solidifies, you will not be afraid of freezing.

The concrete is not afraid of freezing with antifreeze in winter, but the temperature of freezing is reduced, so that the brother is not easy to freeze.

The purpose of adding antifreeze to concrete is to delay the effective time of construction. For example, the original Acacia 0 degree concrete does not set properly. With the addition of antifreeze, it can be lowered to -5 degrees. But still afraid of freezing.